Research Interests:

• Catalysis
• Supercritical Fluids
• Graphite Nanofibers
• Ruthenium Complexes

      Our research group currently has three major focuses: a) catalysis in supercritical fluids, b) the use of graphite nanofibers as catalyst supports, and c) synthesis of novel coordination complexes.

      a) One important problem associated with the use of heterogeneous catalysts is the difficulty in attaining and maintaining high diffusion rates of the substrate to, and through, the solid catalyst.  To address this problem, reactions are typically run using gas phase substrates over solid catalysts.  Unfortunately, the high temperatures that are often required to vaporize the substrates can result in both a loss of product selectivity and catalyst decomposition; thus, we are investigating the use of supercritical fluids (SCFs) as a reaction medium.  SCF can often dissolve both the substrate and products, while maintaining high diffusion rates at lower temperatures.  Additionally, SC CO₂ is much more environmentally-friendly than many traditional liquid phase solvents.  We are currently focused on the isomerization of a-pinene oxide over NaY zeolite catalysts as a model reaction for our SCF studies.  The product, campholenic aldehyde, is of particular interest as a precursor for fragrance chemicals (e.g., santalol) in the perfume, flavor, cosmetic and pharmaceutical industries.         

      b) Gel bi-propulsion systems can be used as simple boosters and variable thrusters for NASA launch vehicles, spacecraft and satellites as well as bi-propellant systems utilizing advanced management for increased tactical missiles.  The increased safety of gels over current hypergolic liquids and high energy density solid propellants decreases hazards of manned space flights and reduces handling and transportation risks in ground operations.  We are synthesizing carbon nanofibers for use in candidate fuel gels.

      c) We have successfully synthesized a series of ruthenium(II) complexes in which the trans-positions of the coordination octahedron are spanned via a unique in situ procedure.  Interest in such trans-spanned complexes stems from their implied ability to demonstrate guest-host reactivities and to mimic naturally occurring enzymes and metalloreceptors.  ¹H and ¹³C NMR studies have shown that the spanning linkage freely rotates and thus, the complexes act as a "molecular gyroscope".  We are currently synthesizing new families of complexes with more rigid pockets for catalytic activity.